More specifically, the invention proposes an impeller of the type comprising: a central hub which is intended to be connected to the rotor of an electric motor, and from which a plurality of blades extends, the hub having a substantially bowl-like shape, with an end wall connected to an annular lateral wall which is at least approximately cylindrical, the end wall having a plurality of slots, spaced apart circumferentially, which are inclined in the same direction with respect to the radial direction, the inner surface of said end wall having a plurality of ribs protruding from this surface, between said slots, these ribs also being inclined in said same direction with respect to the radial direction and being adapted to serve as inner fan blades.
In operation, vibrations generated by the electric motor driving the impeller are transmitted to the impeller, and may cause the generation of acoustic noise at frequencies that are annoying to the human ear, particularly at low speeds.